Multiple seed on paper/steel on two locations, passphrase in head and separately in inheritance with instructions for family. I find this easy to implement and good backups storage scheme. Resitant to discovery of seed (passphrase in head) and remote theft because you only use a good hardware wallet. Than you can have a spending LN wallets in your phone with lower level of security (and amount) and even smaller amount on mobile or web based custodial LN wallet.

There is no usafe custodial - only too many sats at risk. Keep only necesary minimum for zaps on custodial solutions.

Your custodial LN wallet might be more secure than your physical fiat cash wallet.